The present invention relates to a bend angle measuring method for measuring a bend angle of a product which has been subjected to bending work by a bending machine and an apparatus therefor, and an angle measuring system using the apparatus.
With reference to FIG. 13, it is conventionally common to use a protractor 101 when a bend angle of a workpiece W which has been subjected to bending work by a bending machine is measured. The protractor 101 is structured with a base 103 serving as a reference, a rotating member 107 rotatably provided to the base 103 by a pin 105 and an angle indicating plate 109 for indicating the angle of the rotating member 107 to the base 103.
In a angle measurement using the protractor 101, a side WA of the workpiece W serving as the reference at a time of measurement is caused to abut on the base 103 and another side WB of the workpiece W which has been bent is caused to abut on the rotating member 107 with its whole surface, so that an angle measurement is performed by reading the angle of the rotating member 107 from the angle indicating plate 109 at this time.
However, in an angle measurement using such a protractor 101, there is a problem that, when the workpiece W is brought into area contact with the base 103 and the rotating member 107, a worker grasps the workpiece W and the base 103 in his/her one hand, while swings the rotating member 107 in his/her other hand to bring the rotating member 107 into area contact with the workpiece W which has been bent without any clearance, and he/she must read the bend angle of the workpiece W, which is very troublesome and requires much time.
In this circumstance, as shown in Japanese Patent Application Laid-Open No. 6-262265 publication, the present applicant has proposed that one side of a bent workpiece W is sucked to a reference side of an angle measuring apparatus and another bent side of the workpiece W is also sucked to a measuring side of the angle measuring apparatus to be brought into close contact therewith so that measurement of an accurate bend angle is performed.
However, in the angle measuring apparatus shown in the above-mentioned Japanese Patent Application Laid-Open No. 6-262265 publication, an accurate angle measurement can be performed, but there is a problem that the angle measuring apparatus is complicated and is large-scaled.
Accordingly, the present invention has been made in view of the above conventional art, and an object thereof is to provide a bend angle measuring method which can perform bend angle measurement easily, quickly and accurately using a small-sized and light apparatus, and an apparatus therefor as well as an angle measuring system using this apparatus.
In order to achieve the above object, a bent angle measuring method of the invention according to a first aspect comprises the steps of: causing one side of a workpiece which has been bent by a bending machine to abut on a first supporting member serving as a reference surface; sliding the workpiece in a state where the one side of the workpiece has been caused to abut on the first supporting member; pressing another bent side of the workpiece on to a rotatable rotor to come in close contact with the rotor; adjusting a height position of the of the first supporting member relative to the rotation center of the rotor; setting the rotation center within a contact range of the rotor and the workpiece; and reading the rotation angle of the rotor to obtain a bend angle of the workpiece in a state of the above step.
In the above bend angle measuring method, when a workpiece whose bend angle is to be measured is slid to be pressed on to the rotor in a state where the workpiece is caused to abut on the first supporting member serving as the first reference surface, the rotor is rotated, so that the bend angle of the workpiece is measured from the rotation angle of the rotor. At this time, the height position of the first supporting member is adjusted relative to the rotation center of the rotor, so that the rotation center is positioned within a contact range of the workpiece and the rotor.
Accordingly, the rotor is rotated to come in close contact with the workpiece only by pressing the workpiece on to the rotor so that an accurate angle measurement can be performed in a short time.
A bend angle measuring method of the invention according to a second aspect in the bend angle measuring method of the first aspect is characterized in that the rotation angle of the rotor is obtained by reading a scale provided at an outer periphery of the rotor and from a difference between the division of the scale showing a predetermined rotation position of the rotor and a value of the scale when the another side of the workpiece is brought into close contact with the rotor.
Accordingly, the rotation angle of the rotor can be read by reading the division of the scale provided at an outer periphery of the rotor and from a difference between the division of the scale to a predetermined angle of the rotor and the division of the scale obtained when the rotor is caused to abut on the workpiece.
A bend angle measuring apparatus of the invention according to a third aspect comprises: a first supporting member for supporting one side of a workpiece which has been bent by a bending machine; a second supporting member provided at one side of the first supporting member in a standing manner; a rotor which is provided rotatably about a rotation center shaft provided on the second supporting member and which is caused to abut on another side of the workpiece; and a detector for reading the rotation angle of the rotor, wherein the first supporting member is provided such that the height position thereof is adjustable in order to set the relative height position of the rotation center shaft within a contact range of the rotor and the workpiece.
In the above-mentioned bend angle measuring apparatus, when a workpiece whose bend angle is to be measured is slid to be pressed on to the rotor in a state where the workpiece is caused to abut on the first supporting member serving as the first reference surface, the rotor is rotated about the rotation center shaft provided on the second supporting member, so that the bend angle of the workpiece can be measured by reading the rotation angle of the rotor by the detector. At this time, adjustment of the height position of the first supporting member to the rotation center of the rotor is performed so that the rotation center is positioned within the contact range of the workpiece and the rotor.
Accordingly, the rotor is rotated to come in close contact with the workpiece only by pressing the workpiece on to the rotor, so that an accurate angle measurement can be performed in a short time.
A bend angle measuring apparatus of the invention according to a fourth aspect in the bend angle measuring apparatus of the third aspect further comprises a projection for calibration which is provided at the rotor in a projecting manner; and a stopper which is provided at the second supporting member and on which the projection abuts when the rotor is rotated at a predetermined angle.
In the above-mentioned bend angle measuring apparatus, calibration is performed by rotating the rotor to cause the projection to abut on the stopper provided on the second supporting member prior to measurement of the bend angle.
Accordingly, the calibration can be performed easily and quickly.
In a bend angle measuring apparatus of the invention according to a fifth aspect in the bend angle measuring apparatus of the fourth aspect, the stopper has a taper portion or an eccentric portion for allowing adjustment of the position where the projection provided on the rotor is retained.
In the above-mentioned bend angle measuring apparatus, when the calibration is performed by rotating the rotor, the stopper provided on the second supporting member is adjusted and a position on which the projection of the rotor comprising the taper portion or the eccentric portion abuts is adjusted so that fine adjustment for the calibration is performed.
Accordingly, an accurate angle measurement can be performed.
A bend angle measuring apparatus of the invention according to a sixth aspect in the bend angle measuring apparatus of the third aspect is provided with a transmitter for transmitting the rotation angle of the rotor which has been read by the detector to the bending machine by radio.
In the above-mentioned bend angle measuring apparatus, the bend angle of the workpiece which has been measured by the bend angle measuring apparatus is transmitted to the bending machine by radio.
Accordingly, it becomes unnecessary to input the bending angle as data in the bending machine so that workability can be improved.
A bend angle measuring system of the invention according to seventh aspect comprises: a bending machine for bending a workpiece; a bend angle measuring apparatus for detecting the bend angle of the workpiece which has been bent by the bending machine; and a transmitter for transmitting the angle which has been measured by the bend angle measuring apparatus to the bending machine via radio or cable.
In the above-mentioned bend angle measuring system, the bend angle of the workpiece which has been bent by the bending machine is measured by the bend angle measuring apparatus, and the measurement signal is transmitted to the bending machine by the transmitter through radio or cable.
Accordingly, it becomes unnecessary to input the measured bend angle as data in the bending machine so that workability can be improved.
In a bend angle measuring system of the invention according to an eighth aspect in the bend angle measuring system of the seventh aspect, a spring back amount is obtained from a measurement signal after the spring back of the workpiece, which has been transmitted by the transmitter, and a bend angle before spring, which has been measured by an indicator provided on the bending machine; and the spring back amount is stored in a memory of a control device provided in the bending machine.
In the above-mentioned bend angle measuring system, the bend angle after spring back of the workpiece which has been bent is transmitted from the transmitter of the bend angle measuring apparatus to the control device of the bending machine, and the bend angle before spring back which has been measured by the indicator provided on the bending machine is taken in the control device of the bending machine so that the spring back amount is calculated and stored in the memory.
Accordingly, in a case that working conditions similar to the above are applied to bending works subsequent to this bending work, it becomes possible to perform a desired bending work accurately without performing a trial bending.